Suspension for operating room overhead lights

ABSTRACT

A horizontal, telescoping arm and a vertical, telescoping arm are interconnected, one of the arms being fixed to the ceiling and the other supporting an operating light fixture. A motor is connected to the vertical telescoping arm to move the light in a vertical direction, by moving one of the telescoping arm members with respect to the other, the motor being controlled by a sensing element sensing vertical force components applied to the light fixture. The motor may be electric, or a fluid motor (hydraulic or pneumatic), the motor power being controlled over a servoamplifier (or servo valve) which, in turn, is controlled from a bridge circuit of which the sensing element forms a part. The light fixture, itself, is suspended to swing about a horizontal axis, and limit switches are provided to disable operation of the motor when the fixture is deflected about an angle exceeding a predetermined limit.

United States Patent [54] SUSPENSION FOR OPERATING ROOM OVERHEAD LIGHTS8 Claims, 3 Drawing Figs.

[52] [1.5. CI 248/333, 240/1.4, 318/488 [51] Int. Cl F2lv 33/00 [50]Field ofSearch 248/17, 16,

[56] References Cited UNITED STATES PATENTS 7/ 195 6 Brier 2,911,51911/1959 Phillips et a1. 240/1.4 3,087,636 4/1963 Weaver 214/1 X FOREIGNPATENTS 859,162 1/1961 Great Britain 214/1 Primary Examiner-J. FranklinFoss Attorney- Flynn & F rishauf ABSTRACT: A horizontal, telescoping armand a vertical, telescoping arm are interconnected, one of the armsbeing fixed to the ceiling and the other supporting an operating lightfixture. A motor is connected to the vertical telescoping arm to movethe light in a vertical direction, by moving one of the telescoping armmembers with respect to the other, the motor being controlled by asensing element sensing vertical force components applied to the lightfixture. The motor may be electric, or a fluid motor (hydraulic orpneumatic), the motor power being controlled over a servoamplifier (orservo valve) which, in turn, is controlled from a bridge circuit ofwhich the sensing element forms a part. The light fixture, itself, issuspended to swing about a horizontal axis, and limit switches areprovided to disable operation of the motor when the fixture is deflectedabout an angle exceeding a predetermined limit.

PATENTEU AUG 1 719?:

KLAUS JUNGINGER Inventor:

SUSPENSION FOR OPERATING ROOM OVERHEAD LIGHTS The present inventionrelates to a suspension for an over head operating room light, and moreparticularly to a suspension which permits movement of the overheadlight in a vertical. as well as a horizontal direction and requiring aminimum of effort on part of the operator.

Operating room lights must be so constructed that the light will reachany desired region at an operating table, and to enable the position ofthe light fixture itself to be changed without requiring substantialforce. Yet, such operating room lights are usually heavy since they arespecially designed to provide a large area light source so that shadowscan be avoided.

Operating room fixtures are usually supported by both vertical andhorizontal arms, interconnected by links or joints. The joints are soconstructed that they can be rotated with respect to each other, thelinks interconnecting the joints being, however, of fixed length.Movement of the light is limited by the length of the arms themselves,and the permitted swinging of the joints themselves is again limited dueto the large weight of the light fixture. In order to provide evenillumination over a wide region, it is desirable to be able to move theoperating room lights over a wider range, which is difficult to obtainwhen rotatingjoints are employed.

It is an object of the present invention to provide a suspension foroverhead operating room lights which can be easily controlled by aminimum of manual force, and the position of which will be retainedafter the light is in its desired position.

SUBJECT MATTER OF THE PRESENT INVENTION Briefly, a power-assistedsuspension is provided; a pair of arms, one horizontal and one vertical,are interconnected, each arm having mutually telescoping members. Thevertical arm has a motor secured thereto to move the relativelytelescoping members with respect to each other. The operation of themotor is controlled through a control circuit, in turn controlled by asensor responsive to vertical force components applied to the lightfixture. Preferably, the light fixture itself is mounted for swingingmovement, with limit switches being provided to inhibit operation of themotor when the fixture is displaced over an angle exceeding apredetermined value. The motor itself may be an electric motor, or ahydraulic or pneumatic motor.

The invention will be described by way of example with reference to theaccompanying drawings, wherein:

FIG. 1 is a schematic side view of an operating room light andillustrating the suspension;

FIG. 2 is a fragmentary view, to an enlarged scale, of the suspension ofthe operating room light; and

FIG. 3 is a part of the fragmentary view of Fig. 2 and illustratingcontrol of the suspension by means of a fluid motor.

The entire light fixture suspension includes a vertical rotary joint 12,to which a horizontal arm is attached having a pair of telescopingmembers 14, 16. The horizontal arm can swing about the axis of thevertical rotary suspension 12. All arms and suspensions are hollow, theinterior of the arms and suspensions accommodating the electrical supplycable, as well lrnown in the art, to supply electric current to lightfixture 26. Additionally, operating power, which may be electrical,hydraulic, or pneumatic can be conducted to the power assist motor forthe vertical suspension, as will appear below.

A vertical arm 18, likewise formed of an outer and an inner part totelescope within each other is connected to a horizontal telescopingarm. Light fixture 26 is secured to arm 18 by means ofa fork 24. Thevertical arm 18 may be secured to the horizontal arm in such a mannerthat it can swing about a vertical axis.

Illustrated at the end of light fixture 26 is a force triangle, in whicha moving force 42 is shown as broken up into a horizontal and a verticalcomponent. To move the lamp in a horizontal direction, for example, fromthe full line position (Fig. l)

to the chain-dotted position, the horizontal force will cause thetelescoping arm 16 to pull away from arm 14. Vertical movement, inaccordance with the vertical force component is governed by a motor 36(Fig. 2). Vertical arm l8 has an outer member 19 and an inner member19'. The inner member 119 has an inside thread 20 formed thereon, whichengages a threaded spindle 21, driven over suitable gearing, for examplea worm gear, by the motor 36. Thus, the motor will control the verticalposition of the lamp attached to the vertical arm 18. Suitable means areprovided to prevent relative rotation between the two members l9, l9.

The motor is controlled by a control system 30, which is connected to asensing device 56, shown as a pressure-measuring diaphragm having astrain transducer therein. Motor 36, itself, is mounted at the top ofarm 18. The strain transducer 56 is mechanically connected to a joint 22(Fig. l) to which fixture connecting arm 44 is attached, merging intofork The fixture 26, itself, can swing about a horizontal axis indicatedat 28. Joint 22 provides for swinging of arm didabout a vertical axis.By giving maximum freedom of movement for the joints, that is bypermitting close to 180 rotation of the relatively movable parts,practically any field can be illuminated, from the top, or from anyside. A handle 46 is secured to a forlr extension 48, or to the lightfixture itself, to move the light fixture and to apply the forcecomponent 42.

Application of force 42 to the handle 46, and thus over fork 48 appliesstrain to the transducer element 56. When the transducer element 56 isstrained, or deflected beyond a predetermined limit, causes controlsignal can be derived therefrom. Preferably, the transducer elementforms one arm of a bridge circuit, and is connected by means of line 3 Eto a combination bridge and servoamplifier 32. Under static operatingconditions, the bridge is so adjusted that it is in balance, so thatservoamplifier 32 will not apply power to electric motor 36. Applicationof a force d2, however, for ex ample to raise the fixture 26, causes anupwardly directed component of force. As an example, the gauge willdeflect, or compress, change its resistance, and apply an error signalover line 34 to amplifier 32, to control the motor to turn spindle Illin a direction to raise the fixture, the rotation continuing untilbalance is again reestablished. Applying a pull on the fixture, forexample in the direction of force 42 (FIG. 1) causes opposite deflectionof the element 56, a control signal in the opposite direction, androtation of motor 36 in a direction to lower the fixture 26. Thechain-dotted position in FIG. 1 illustrates the greatest movementpossible, both in horizontal as well as in vertical direction. As shown,joint 22 can further be so arranged to swing not only over a verticalaxis 50, but also over a horizontal axis to obtain even greater range ofpossible illumination. The strain gauge is preferably so arranged tohave a predetermined threshold value, so that it will not be toosensitive, and not be activated upon touching of the light fixture, orsmall movements thereof.

FIGS. 1 and 2 illustrate the arrangement utilizing an electric motor.FIG. 3 illustrates the adaptation of the system with a fluid motor, forexample a hydraulic motor. The output of the servoamplifier 32 is brokenat point X-X and applied to a servovalve 132, having a pressure input33, the o tput from pressure input 133 being conducted over either an upline 134 or a down line 135 to the fluid motor lilo. Return line 137connects to the source of pressure supply, not shown, for recirculationto input line 133. All other parts may be similar to those shown in FIG.2 and therefore are not further illustrated because they have beenpreviously completely described. The potential resulting from imbalanceof the bridge, applied to the servoamplifier, controls the servov'ilvewhich is a multipath, multiposition valve (for example a wellknown servospool valve) forming a fluid circuit to the or to the down" line fromthe input, as desired, in order to control the operating force to fluidmotor 136 in accordance with the desired direction and extent of motion.

Immediate stopping, or interruption of motion of motor as (or 136) isfrequently desired, particularly when the joint 2?.

(FIG. 1) permits swinging about a horizontalaxis. lf the operator wishesto avoid movement of motor 36 for displacement in a vertical direction,a disabling circuit formed of member 52 and contacts 54, 54', togetherwith an electrical circuit line 40 and switches 41, 41' is provided. theswitches being shown in closed position. Switches 54, 54' are limitswitches attached to a pair of extending diverging members and securedto fork 24. Upon movement of fork 48 over the axis 28 beyond apredetermined angle, limit switches 54, or 54, respectively, will becontacted, causing operation of switches 41, 41', respectively, asindicated by the dashed lines, for example over a relay connection aswell known. Operating force 42 can thus be applied to handles 46 andwill cause vertical displacement until additional swinging motion isimparted to the light fixture whereupon motor 36 is stopped immediately.Of course, a similar interrupt system can be applied to the embodimentillustrated in connection with FIG. 3.

The power assisted vertical movement permits placement of even heaviestoperating room light fixtures in any desired position with a minimumamount of force being necessary on part of the operator, whilepermitting a wide choice of field to be illuminated. Variousmodifications and changes may be made within the scope of the inventiveconcept.

l claim:

1. Operating room overhead light suspension adapted to be mounted on aceiling to support an'operating room light fixture comprising:

a horizontal arm (14, 16) having two mutually telescoping members;

a vertical arm (18) having two mutually telescoping members, one of saidarms being mounted on the ceiling and the other arm having a lightfixture secured to an end thereof;

a motor (36) secured to said vertical arm and connected to move one ofsaid vertical telescoping members with respect to the other;

sensing means (56) sensing a vertical movement force component appliedto said light fixture and additional to the dead weight suspended onsaid other arm;

and control means (32, 34) connected to and controlling operation ofsaid motor under command of said sensing means when the sensed movementforce in the vertical direction exceeds a predetermined level.

2. Suspension according to claim 11, wherein said sensing means is apressure gauge (56) having an electrical strain transducer therein andmounted inside said vertical arm, said control means including a bridgenetwork having said strain transducer connected in one arm thereof.

3. Suspension according to claim 1, wherein sa d motor is an electricmotor.

4. Suspension according to claim 2, wherein said motor is an electricmotor, said bridge network is connected to a servoamplifier, said motorbeing controlled in amount and direction by an unbalance signal of thebridge transmitted to said servoamplifier.

5. Suspension according to claim 1, wherein said motor is a fluid motor.

6. Suspension according to claim 2, wherein said motor is a fluid motor,the output of said bridge network controlling a servovalve, saidservovalve being connected to control fluid supply to said motor.

7. Suspension according to claim 1, wherein said light fixture (26) isswingably mounted to swing about a horizontal axis (28);

means (52, 54) sensing swinging movement of said fixtures are provided,said swing-sensing means being connected to said motor and inhibitingoperation of said motor upon sensing of swinging of said fixture above apredetermined angle.

8. Suspension according to claim 7, wherein said means sensing swingingmovement of said light fixture includes a pair of limit switches locatedadjacent the axis about which the light fixture may swing, said limitswitches beingl connected to interrupt appllcation of power to saidmotor w en deflection of the light fixture about said axis exceeds apredetermined limit.

1. Operating room overhead light suspension adapted to be mounted on aceiling to support an operating room light fixture comprising: ahorizontal arm (14, 16) having two mutually telescoping members; avertical arm (18) having two mutually telescoping members, one of saidarms being mounted on the ceiling and the other arm having a lightfixture secured to an end thereof; a motor (36) secured to said verticalarm and connected to move one of said vertical telescoping members withrespect to the other; sensing means (56) sensing a vertical movementforce component applied to said light fixtuRe and additional to the deadweight suspended on said other arm; and control means (32, 34) connectedto and controlling operation of said motor under command of said sensingmeans when the sensed movement force in the vertical direction exceeds apredetermined level.
 2. Suspension according to claim 1, wherein saidsensing means is a pressure gauge (56) having an electrical straintransducer therein and mounted inside said vertical arm, said controlmeans including a bridge network having said strain transducer connectedin one arm thereof.
 3. Suspension according to claim 1, wherein saidmotor is an electric motor.
 4. Suspension according to claim 2, whereinsaid motor is an electric motor, said bridge network is connected to aservoamplifier, said motor being controlled in amount and direction byan unbalance signal of the bridge transmitted to said servoamplifier. 5.Suspension according to claim 1, wherein said motor is a fluid motor. 6.Suspension according to claim 2, wherein said motor is a fluid motor,the output of said bridge network controlling a servovalve, saidservovalve being connected to control fluid supply to said motor. 7.Suspension according to claim 1, wherein said light fixture (26) isswingably mounted to swing about a horizontal axis (28); means (52, 54)sensing swinging movement of said fixtures are provided, saidswing-sensing means being connected to said motor and inhibitingoperation of said motor upon sensing of swinging of said fixture above apredetermined angle.
 8. Suspension according to claim 7, wherein saidmeans sensing swinging movement of said light fixture includes a pair oflimit switches located adjacent the axis about which the light fixturemay swing, said limit switches being connected to interrupt applicationof power to said motor when deflection of the light fixture about saidaxis exceeds a predetermined limit.